PLATE XLVT. 



Pleurotoimaria l^PENCERi (page 341). 



Figure i. Upper surface of an immature speeimen from an exposure at the moutli 

 of the Keil Deer Rivei', in Dawson Bay, shewing the inere- 

 mental stri;e (somewhat (liagi'ainmatieally) curving o}>li(piely 

 baekwaril to the slit liaud. Drawn from a gutta peroha impres- 

 sion of a niouhl of the exterior of the slirlL 



HVOLITIIES ALATUS (]>ag(^ 342). 



Figure -. Side view nf a cast of the interidi of tlie shell, from South Manitou 



Island, Lake ^Vinni]>egosis. 

 Figure 'A. Anterior moiety of another specimen from the same locality, "in whicli 



the central portion and one of the lii'oad lateral wings of the 



dorsal surface are well exhihited, with tlie lines of growth and 



shape of the lip on that side." 

 Figuie 4. Outline of transverse section of the shell of another specimen, from the 



western shore of Dawson Kay, north of Steep F-lock River. 



Bronteus MANiT(tBEN.sis (page 347). 



Figure 5. The specimen from a small island north of Whileaves Point, Dawson 

 Bay, referred to mthe text as "Specimen No. 1." 



Figure 6. The specimen from Pentanierus Point, Lnke Manitol)a, referied to in 

 the text as " Specimen No. .S. " 



Figure 7. The specimen from Rowan Island, in Dawson Bay, referred ti> in tlie 

 text as "Specimen No. .">." 



LiCHAS (Terataspis). N. Sp. (page 349). 



Figure S. I'ortion of the marginal spines of the pygidium fnnn Rowan Island, 

 Dawson Bay, referied to in the text. Drawn fron* n gutta 

 pereha impression of a natural mould, in dolomite, of theextc 

 rior of tliese spines. 



Cypiiaspis beltaila (p;i.^e 349). 



Figure 0. A cephalic sliield of this species, from one of the small islands in Dawson 



I^ay, as seen from above. 

 Figure 9a. Side vie\\' of the same, in outline, to shew the proportitniate convexity. 



Proetu.s mumu'lus (pago 350). 



Figure 10. Restoration of this species, in outline, as far as wariaiited liy actual 

 specimens. The charaL-lers of the genal angles of the cephalic 

 shield, and those of tlie genal spiut^'s, if there were any, are 

 nnknow 11. 



Figure 1 1, (Glabella of a specimen, from a small island ninth of \Vhitea\es Point, 

 Dawson Bay, twice the natiu'al size, to shew the surface mark- 

 ings and glal)ellar furrows, as well as the occipital furrow and 

 ring. 



DiNicnTiivs Cawdensis (page 353). 



Figure IL*. View of the e\tetinr of the only sjtecimen colleeled, from Siuikc Island, 

 Lake W'innipegosis, of the " premaxillary *' tooth or dental 

 plate of this s[M.'eies. 



